From beginning to end, pregnancy involves all kinds of tests, and some are less pleasant than others. Amy Schumer, who revealed her pregnancy in October, recently shared on Instagram that she was undergoing glucose testing, which definitely looked like it was on the unpleasant end of the spectrum.

“Fingers crossed sisters,” Schumer captioned a photo of herself drinking a bright orange liquid called Sun-Dex. Some of her followers asked in the comments what the test was for, while others who had been through it relayed their tales of drinking the same oddly colored drink.

Pregnant people undergo this type of glucose screening to test for gestational diabetes.

If you have gestational diabetes, your body passes more sugar to your baby that it needs, ACOG explains. That can cause your baby to gain a lot of weight and cause complications for you, including labor difficulties, the need for a C-section, heavy bleeding after delivery, and severe tears in your vagina. It also raises your risk for high blood pressure during pregnancy, which can place extra stress on your heart and kidneys.

The glucose screening usually happens near the end of the second trimester, between 24 and 28 weeks of pregnancy. It may be done in one or two steps: The standard two-step version of the test starts with a one-hour test that’s recommended for all pregnant people. Then, if your results on the one-hour test show that you have too much glucose in your blood, you may then be required to complete a three-hour test, MedlinePlus explains. In the single-step version of the test, the whole thing is done in two hours.

The test you get depends on your doctor and their preference. No matter which test you're given, though, they all look for the same thing: to see how your body and blood sugar responds to receiving a load of glucose, Christine Greves, M.D., a board-certified ob/gyn at the Winnie Palmer Hospital for Women and Babies, tells SELF.

You don’t have to do much to prepare for the one-hour glucose screening.

You don't need to change your normal diet before the test. “Go ahead and have the type of breakfast that you normally would,” Dr. Greves says. “We want to see how your body processes sugar on a daily basis.”

Once you go in to your doctor’s office or local lab for the test, you’ll be handed a bottle of liquid that contains glucose, like the one that Amy posed with. This usually contains 50 grams of glucose. “It’s a really sweet drink that’s lightly carbonated. The reason it’s so sweet is because of all the glucose,” G. Thomas Ruiz, M.D., lead ob/gyn at MemorialCare Orange Coast Medical Center in Fountain Valley, California, tells SELF.

After you drink the beverage, you’ll be asked to wait for an hour. During that time, you should avoid eating anything and keep drinking water to a minimum, since doing either can throw off the test, Dr. Greves says. When the hour is up, your blood will be drawn to check your blood glucose levels, and you’ll be sent on your way. The amount of time it takes to get your test results varies by lab and doctor’s office. Some will give you results the next day, but others can take up to a week, Dr. Greves says.

Most of the time, a normal result for the glucose screening test is a blood sugar that is equal to or less than 140 mg/dL one hour after drinking the sweet beverage, MedlinePlus says. If you get a normal result, that suggests you don’t have gestational diabetes. (Schumer posted a few days later confirming that she passed her test.)

If your blood glucose levels are too high after the one-hour test, you’ll be asked to take the three-hour test.

This one is a little more intense. For starters, you’re not supposed to eat or drink anything other than sips of water for 8 to 14 hours before this test, according to MedlinePlus.

When you get to your doctor’s office or lab, they’ll draw your blood and then hand you another super sweet drink to enjoy (this time it will likely contain 100 grams of glucose). Then, you’ll have your blood drawn three more times—every 60 minutes from the time you first had the drink. After that, you’ll be sent on your way and, again, you can expect results anywhere from the next day to three days later.

This test looks for abnormalities from each blood draw. So, if the results of only one of your blood tests is higher than normal, your doctor may recommend that you alter your diet and then test you again later, Dr. Greves says. But if more than one of your results is higher than normal, that's an indicator that you might have gestational diabetes, MedlinePlus says.

The two-hour test is pretty similar to the three-hour test.

For this test, you’ll be asked to avoid eating or drinking anything other than sips of water for 8 to 14 hours before your test, the U.S. National Library of Medicine says. Once you arrive at the testing site, you’ll have your blood drawn. Then, you’ll be asked to drink a liquid that has 75 grams of glucose. Your blood will be drawn again two more times every 60 minutes after you drink it. After that, you can go home.

Just like the three-hour test, having an abnormal result from one of the tests doesn’t necessarily mean you have gestational diabetes, but having an abnormal result on two or more of them does.

If your results indicate that you have gestational diabetes, you will probably need to make some changes.

If you’ve been diagnosed with gestational diabetes, your doctor will likely recommend that you make changes to your diet and lifestyle behaviors. They may suggest that you make different, healthy food choices, eat regularly to avoid dips and spikes in your blood sugar level, and/or have three meals and two snacks a day, according to ACOG. Your doctor may also ask you to meet with a dietary counselor or nutritionist, Dr. Ruiz says.

You also may be asked to try to get regular exercise (when you feel up to it), which can also help control your blood sugar levels, ACOG says. From there, you’ll be asked to use a glucose monitor to check your blood sugar levels at home several times a day and to keep a log, either online or on your phone, to help your doctor track everything, ACOG says.

If your glucose levels are under control after some time, your doctor will probably recommend that you still come in for visits more often to monitor your health and your baby’s health. But, if your levels are still off, you may need to start taking insulin injections to help, ACOG says.

Most people who take the glucose screening don’t have gestational diabetes, Dr. Greves notes, so you shouldn’t worry too much about the test. But if you are diagnosed with gestational diabetes, there are plenty of treatment options available to help.